Patent application title: Component Operating on Acoustic Waves

Abstract:

A component operating with acoustic waves is described herein. The
component includes a substrate having an underside subdivided into a
center area and an edge area surrounding die center area on all sides.
The component also includes a plurality of outer terminals in the edge
area, and a plurality of inner terminals in the center area comprising at
least a first inner terminal configured as a signal terminal.

Claims:

1. A component operating with acoustic waves, comprising:a substrate
having an underside subdivided into a center area and an edge area
surrounding the center area on all sides,a plurality of outer terminals
in the edge area, anda plurality of inner terminals in the center area,
comprising at least a first inner terminal configured as a signal
terminal.

2. The component of claim 1, wherein the plurality of inner terminals
comprise at least a second inner terminal configured as a ground
terminal.

3. The component of claim 2,wherein the plurality of outer and inner
terminals on the underside of the substrate form a pin matrix, andwherein
the first and the second inner terminals are in each of two mutually
perpendicular directions between two other terminals of the pin matrix.

4. The component of claim 1, further comprising:a chip mounted on the
substrate having component structures and operating with surface acoustic
waves.

5. The component of claim 1, further comprising:a chip mounted on the
substrate having component structures and operating with bulk acoustic
waves.

6. The component of claim 4, further comprising:a duplexer circuit having
a transmit filter and a receive filter,wherein the transmit filter and
the receive filter are in the chip or on the chip, and connected to at
least some of the plurality of outer and inner terminals via electrical
connections integrated in the substrate.

7. A component operating with acoustic waves, comprising:a substrate
having a first pair of signal terminals and a second pair of signal
terminals on an underside of the substrate,wherein centers of the signal
terminals of the second pair of signal terminals are on a center line
between the signal terminals of the first pair of signal terminals.

8. The component of claim 7, wherein the first pair of signal terminals
are associated with a balanced port.

9. The component of claim 8, further comprising:a duplexer having an
antenna terminal, a transmit input, and a receive output,wherein the
receive output is associated with the balanced port,wherein the second
pair of signal terminals comprise a first terminal and a second terminal,
the first terminal being configured as the antenna terminal and the
second terminal being associated with the transmit input.

10. The component of claim 9,wherein the antenna terminal is between a
signal terminal of the transmit input and signal terminals of the receive
output.

11. The component of claim 10, further comprising:a first ground terminal
between the antenna terminal and the signal terminal of the transmit
input, anda second ground terminal between the antenna terminal and the
signal terminals of the receive output.

12. The component of claim 11,wherein the first and the second ground
terminals have a first surface area,wherein the signal terminals of the
first pair of signal terminals and the signal terminals of the second
pair of signal terminals have a second surface area, the first surface
area being larger than the second surface area.

13. The component of claim 1,wherein the plurality of outer and inner
terminals comprise at least two successive first and second terminals
with different widths,wherein the first terminal is configured as a
signal terminal and has a first width, and the second terminal is
configured as a ground terminal and has a second width, the first width
being smaller than the second width.

14. The component of claim 1,wherein the plurality of outer and inner
terminals comprise at least two successive first and second terminals
with different surface areas,wherein the first terminal is configured as
a signal terminal and has a first surface area, and the second terminal
configured as a ground terminal has a second surface area, the first
surface area being smaller than the second surface area.

15. A component of operating with acoustic waves, comprising:a substrate
having an underside including at least three terminals one alongside the
other in a direction,wherein at least a first terminal and a second
terminal of the three terminals have different widths.

16. The component of claim 15, wherein a ratio of the different widths is
between about 1 and 2.

17. The component of claim 15,wherein the first terminal having a smaller
width is a signal terminal and the second terminal having a larger width
is a ground terminal.

18. The component of claim 1, wherein the plurality of outer and inner
terminals on the underside are suitable for surface mounting.

19. The component of claim 1, further comprising:a plurality of ground and
signal terminals configured one alongside the other in one direction,
having a varying distance between successive terminals.

20. The component of claim 19,wherein the distance between at least one of
the signal terminals and an adjacent terminal is selected to be larger
than the distance between two adjacent ground terminals.

21. The component of claim 1,wherein the plurality of outer and inner
terminals are configured as signal terminals and have a first average
size,wherein the plurality of outer and inner terminals are configured as
ground terminals and have a second average size, the first average size
being smaller than the second average size.

22. The component of claim 5, further comprising:a duplexer circuit having
a transmit filter and a receive filter,wherein the transmit filter and
the receive filter are in the chip or on the chip, and connected to the
plurality of outer and inner terminals of the component via electrical
connections integrated in the substrate.

Description:

[0001]Components operating with acoustic waves are known for instance from
the publication U.S. Pat. No. 6,791,437 B2.

[0002]A problem to be solved is to specify a component with a low
crosstalk between two signal paths to be separated from one another.

[0003]According to a first preferred embodiment, a component operating
with acoustic waves is specified comprising a substrate, the underside of
which is divided into an edge area and a center area surrounded on all
sides by the latter. Outer terminals are arranged in the edge area and an
arrangement of inner terminals is arranged in the center area. The
arrangement of inner terminals comprises at least one first inner
terminal, which is provided as a signal terminal.

[0004]The terminals of the component are also referred to as pins or
solder pads. Terminals that are arranged in two mutually perpendicular
preferred directions between two other terminals of the pattern of
terminals, known as a footprint, are referred to as inner terminals. The
preferred directions are, for example, defined parallel to the edges of
the substrate's underside. Those terminals which are arranged in the edge
area of the substrate underside (or outside the center area) are referred
to as outer terminals.

[0005]In one variant, the arrangement of inner terminals has at least one
second inner terminal which is provided as a ground terminal. A (first or
second) inner terminal is positioned such that that it lies in each of
two mutually perpendicular directions between two other terminals, e.g.,
between two outer terminals.

[0006]The substrate is, for example, a multilayer substrate with
metallization planes, between which dielectric layers are arranged. The
substrate is an LTCC substrate, for example. A chip having components
operating with surface acoustic waves and/or bulk acoustic waves is
preferably mounted on the substrate.

[0007]In one variant, a duplexer circuit that comprises a transmit filter
and a receive filter is in the component. These filters have acoustic
resonators that are arranged in the chip or on the chip, for example. The
filters are electrically connected to the inner and the outer terminals
of the component via electrical connections integrated into the
substrate. The duplexer circuit can have an antenna-side matching
network, e.g., a transmission line arranged in the receive path. This
matching network is preferably integrated into the substrate, with its LC
elements or line segments being realized, for instance, by conductor
tracks or conductor areas arranged in the metallization planes.

[0008]According to the second preferred embodiment, a component operating
with acoustic waves is specified, comprising a substrate, on the
underside of which first signal terminals and second signal terminals are
arranged. The center points of the at least two second signal terminals
lie substantially on an imaginary center line that runs in the center
between two first signal terminals.

[0009]The first signal terminals are preferably assigned to a balanced
port that is connected, for example, to a receive path with symmetrical
signaling. The second terminals are preferably each assigned to a
single-ended port.

[0010]In one variant, the component comprises a duplexer with an antenna
terminal, a transmit input and a receive output. The receive output is
preferably assigned to the balanced port. One of the second signal
terminals is provided as an antenna terminal, the other second signal
terminal being assigned to the transmit input.

[0011]The arrangement of the antenna terminal between the signal terminal
of the transmit path and the signal terminals of the receive path is
considered advantageous.

[0012]A first ground terminal can be arranged between the antenna terminal
and the signal terminal of the transmit input. A second ground terminal
can be arranged between the antenna terminal and the signal terminals of
the receive output. Preferably each of these ground terminals has a
larger surface area than the first and second signal terminals.
Additional inner or outer ground terminals can also be provided,
preferably also having a larger surface area than the signal terminals.
Additional signal terminals can also be present.

[0013]In one variant, the terminals comprise two successive terminals with
different surface areas, wherein the terminal with a smaller surface area
is provided as a signal terminal, and the terminal with the larger
surface area is provided as a ground terminal. The terminals comprise for
example, at least two successive terminals with differing widths, wherein
the terminal with the smaller width is provided as a signal terminal and
the terminal with the greater width is provided as a ground terminal.

[0014]According to the second preferred embodiment, a component operating
with acoustic waves is specified, comprising a substrate, the underside
of which comprises at least three terminals arranged one alongside the
other in a preferred direction, wherein at least two of these terminals
have widths differing from one another relative to the preferred
direction. The ratio of the differing widths lies between 1 and 2 in an
advantageous variant, but can in principle also be greater than two.

[0015]A grounding surface, which is arranged in the substrate and is
provided for shielding the circuit elements integrated into the substrate
(in particular, the matching network of the duplexer), can be connected
to a ground terminal. A grounding surface, for example arranged on the
rear side of the chip that is provided for shielding the component
structures integrated in the chip can also be connected to a ground
terminal.

[0016]The terminal with the smaller surface area or width can be provided
in all preferred embodiments of the component as a signal terminal, and
the terminal with the larger surface area can be provided as a ground
terminal. It is advantageous to select an average size of the terminals
provided as signal terminals to be smaller than an average size of the
terminals provided as ground terminals.

[0017]The terminals arranged on the underside of the component can be
suitable for surface mounting in all preferred embodiments.

[0018]In all preferred embodiments of the component, the underside of the
carrier substrate can comprise an arrangement of terminals arranged one
alongside the other in one direction, wherein the distances between
successive terminals can differ from one another. It is provided that, in
particular, relative to at least one preferred direction, the distance
between a signal terminal and the adjacent terminals (ground terminals or
at least one additional signal terminal) is selected to be greater than
the distance between two ground terminals arranged one alongside the
other relative to a preferred direction.

[0019]The arrangement of terminals arranged one alongside the other in a
preferred direction can optionally have terminals that are offset with
respect to one another perpendicular to the preferred direction, so that
their centers do not lie on one line. It is also possible, however, for
the terminals of this arrangement to form a row, wherein their centers or
edges (e.g., edges facing inward or outward with respect to the center of
the substrate) lie on an imaginary line.

[0020]The specified component will be described below on the basis of
schematic figures not drawn to scale.

[0021]FIG. 1 shows the plan view onto the underside of the component, and
its subdivision into an edge area and a center area;

[0022]FIG. 2, an example of a footprint with a pin matrix having inner
terminals;

[0023]FIG. 3, a component in cross section with an acoustic chip that is
mounted on a carrier substrate, on the underside of which inner terminals
are provided;

[0024]FIG. 4, a circuit with a duplexer realized in the component
according to FIGS. 2, 3.

[0025]FIG. 1 shows an imaginary subdivision of the underside of a carrier
substrate TS, shown in FIG. 3 for instance, with an edge area RB and a
center area MB. Edge area RB is an area having the shape of a frame that
faces the outer edges of the carrier substrate. Edge area RB is an area
that is free of inner terminals IA1, IA2. On the other hand, the center
area is an area that is free of outer terminals AA. Terminals AA, IA1 and
IA2 are SMD terminals.

[0026]FIG. 2 shows the footprint (terminal arrangement) of a component
operating with acoustic waves in which a duplexer circuit is realized.
The footprint is realized in the lowermost metallization plane of
substrate TS.

[0027]Outer terminals AA are arranged in edge area RB, and a first inner
terminal TA1 and several second inner terminals IA2 are arranged in
center area MB. The ratio of the widths of the center area and the edge
area can in principle be arbitrary. The width of the edge area is
substantially determined by the length of the outer terminals AA, or the
longest of these terminals. The connecting points between terminals IA1,
IA2 and contact areas, not shown in the figures, of an external circuit
board can be solder pads or bumps, for example.

[0028]Terminal IA1 is a signal terminal and terminals IA2 are ground
terminals. Terminal IA1 in this case is an antenna terminal ANT. All
terminals form a footprint in the form of a pin matrix that has several
rows and five columns.

[0029]Successive terminals in the horizontal direction form a row and
successive terminals in the vertical direction form a column. For
example, the successive terminals GND, GND1, GND6 and GND2 form one row
and the terminals TX, GND1, ANT and GND2 form an additional row.
Terminals GND1, GND2 and RX1 follow one another in a horizontal direction
and therefore form a row. In principle the columns can be interchanged
with the rows in case of a rotation of the footprint by 90°, for
example.

[0030]The first ground terminal GND 1 serves to shield antenna terminal
ANT from the unbalanced-to-ground transmit input, which has a signal
terminal TX. The second ground terminal GND2 serves to shield antenna
terminal ANT from the ground-symmetric receive output, which has two
signal terminals RX1, RX2.

[0031]Additional ground terminals, including terminals GND3, GND4, GND5,
are provided. Apart from the signal terminals RX1, RX2, TX and ANT, all
other terminals are preferably connected to ground. The surface area of
the signal terminals RX1, RX2, TX and ANT is smaller than the surface
area of the ground terminals. It is possible for example, to select the
width L1 of signal terminal TX, measured in the vertical direction, to be
smaller than the width L2 measured in this direction of the ground
terminals GND, GND3 adjacent to this signal terminal.

[0032]The distance between signal terminal TX and the adjacent terminals
GND, GND1, GND3 is preferably larger than the distance between two ground
terminals, e.g., between terminals GND and GND1 or GND4 and GND5. This
also applies to the signal terminals ANT, RX1 and RX2.

[0033]The surface area of the ground terminals GND1, GND2 provided between
two hot terminals is selected to be greater than the surface area of
other ground terminals, which serve, for instance, for ground contact
with a ground contact area in substrate TS.

[0034]The dimensioning and positioning of the terminals of a footprint
explained in connection with FIG. 2, in particular, the relative
dimensioning and positioning of the signal and ground terminals,
represent measures according to the third preferred embodiment of the
component.

[0035]The footprint shown in FIG. 2 has, according to the second preferred
embodiment of the component, first signal terminals 11, 12 and second
signal terminals 21, 22. The center points of second signal terminals 21,
22 lie on an imaginary center line ML that runs in the middle between two
first signal terminals 11, 12.

[0036]The first terminals are preferably equally large and are
mirror-symmetrically arranged relative to line ML, which runs through the
centers of second terminals 21, 22. Thus the same distance of the two
first terminals 11, 12 from terminal 21 and from terminal 22 is
guaranteed.

[0037]First terminals 11, 12 in the variant according to FIG. 2 are signal
terminals RX10, RX2 of a first ground-symmetric receive output. Second
terminal 21 is a signal terminal TX of an unbalanced-to-ground transmit
input. The additional second terminal 22 is an antenna terminal ANT, thus
also a signal terminal of an unbalanced-to-ground electric port.

[0038]FIG. 3 shows an example of a component in cross section. The
component comprises a substrate TS and a chip CH arranged thereon which
comprises component structures operating with acoustic waves.

[0039]Substrate TS comprises several dielectric layers, e.g., LTCC layers.
The dielectric layers of the substrate are arranged between metallization
planes. The metallization planes are conductively connected to one
another by means of plated through-holes. The metallization planes
comprise circuit elements such as inductors, capacitors, or transmission
lines, including the transmission line TL shown in FIG. 4.

[0040]The outer terminals AA, IA1, IA2 of the component, which were
already shown in FIG. 2, are formed in the lowest metallization plane of
carrier substrate TS. In its uppermost metallization plane, contact areas
are formed which can be connected to the terminal areas of chip CH by
means of bumps in a flip chip arrangement of chip CH. The electrical
connection between the contact areas of carrier substrate TS and the
terminal areas of chip CH is alternatively possible by means of bond
wires, in case the rear side of the chip faces towards the carrier
substrate.

[0041]FIG. 4 shows a front end circuit with a signal path that comprises
an antenna path (transmit-receive path) connected to an antenna terminal
ANT, a transmit path connected to a transmit input TX and a receive path
connected to a receive output RX1, RX2.

[0042]Duplexer DU comprises a transmit filter F1 arranged in the transmit
path, a receive filter F2 arranged in receive path RX, and a matching
network that can comprise a transmission line TL arranged in the receive
path.

[0043]Transmission line TL preferably has a quarter wavelength at the
transmit frequency associated with the signal path. A λ/4 line
emulated by LC elements can be used in place of transmission line TL.
These LC elements are preferably integrated in substrate TS.
Alternatively the matching network can also have, for instance, a
parallel inductor and a series capacitor.

[0044]The filters F1, F2 associated with duplexer DU each comprise BAW
resonators and/or at least one SAW transducer. The resonators or
transducers can be interconnected in a ladder-type arrangement, for
example.

[0045]A balun is integrated in receive filter F2 in the variant shown in
FIG. 4. It is also possible to connect a balun, which is preferably
integrated in substrate TS, on the output side of receive filter F2 with
a single-ended output.

[0046]Different measures explained above for designing a footprint can be
arbitrarily combined with one another.